Method and apparatus for electrostatically painting parts made of dielectric or low-conductivity material

ABSTRACT

A method for painting a parts made of dielectric or low-conductivity material using a paint spraying unit including a chamber connected to both a paint outlet and to a paint supply. At least one electrode is mechanically and electrically connected to the part. An electrostatic field is generated between the electrode and the paint spraying unit. Paint is fed from the paint supply through the chamber to the outlet. The paint is electrically charged. The paint is sprayed onto the part to be painted. The outer surface of the electrode used includes at least one jagged portion for engaging the part to be painted. The jagged portion is the location of a peak electrostatic effect.

TECHNICAL FIELD

The instant invention teaches a method for painting parts made ofdielectric or low-conductivity material, an electrode for painting partsmade of dielectric or low-conductivity material and an apparatus forpainting parts made of dielectric or low-conductivity material

The instant invention applies particularly to the carpentry andfurniture industries.

BACKGROUND ART

The current methods for painting on wood involve sanding, staining,waiting for the stain to dry, peeling off the stain, applying a liquidfinish, waiting for the liquid finish to dry and then repeating thisprocess several times, often as many as seven times. The edges of theboards are treated separately and the two faces must be treated severaltimes. The entire process, therefore, takes two and a half days (for abasic finish) or up to four days (for complex forms involving moldings,cuttings and grooves). Additionally, the liquid finishes are notguaranteed to hold more than one, or maybe a few years. The spectrum ofcolors is forcibly very limited. Finally, the coats of finish must beapplied evenly; in other words, the number of coats on the two facesgenerally must be the same, or the board will appear shaded.

Other methods for finishing wood involve coating the faces of the boardwith a sheet of laminated paper or veneering. Complex forms are,therefore, difficult to finish, if not impossible, by such a means ofmanufacture. The coatings and their bondings with the wood are oflimited value against impacts to the wood.

Finally, a last method involves applying, by way of pressure and heat, afilm of plastic material of different color and structure on one faceand the four edges. This method cannot be used to cover the entirety ofa board in one application. Further, the natural grain of the face ofthe wood may allow the film to show through The choice of colors here,too, is very limited.

The instant invention seeks to resolve these problems by proposing amethod of painting parts made of dielectric or low-conductivity materialin particular wood, an electrode and an apparatus for painting on saidmaterials using said method.

SUMMARY OF THE INVENTION

The method described in the instant invention is a method for paintingparts made of dielectric or low-conductivity material in which apaint-spraying unit including a chamber connected to both a paint outletand a paint supply is used. This method essentially involvesmechanically and electrically connecting at least one electrode to thepart to be painted, creating an electrostatic field between theelectrode and the paint spraying unit by applying a difference ofelectrical potential between the electrode and another electrode lodgedin the chamber of the paint spraying unit, feeding the paint from thepaint supply through the chamber to the outlet, electrically chargingthe paint and spraying said paint onto the part to be painted.

A solid paint in powdered form is the preferred paint to be used. Forexample, a polyester-based, powdered paint could be used.

According to another embodiment, the method of painting involvesinserting the electrode into the part to be painted. This embodimentallows for painting all external surfaces of the part to be painted.

In variation, the method of painting involves placing an electrode on atleast one of the external faces of the part to be painted. Such a methodlimits painting to those faces not covered by the electrode(s).

The electrode according to the invention for electrostatically paintingparts made of dielectric or low-conductivity material, intended to comeinto contact with the part to be painted and to be connected to one ofthe two poles of a source of electrical power contained in theapparatus, is essentially characterized by its exterior surface whichcontains at least one jagged portion for engaging the part to bepainted, said jagged portion being the location of the so-called peakelectrostatic effect.

The description which follows, referring to the attached drawings forexplanatory, but not limiting, purposes allows for a betterunderstanding of the advantages, goals and characteristics of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a succession of operations according to the instantinvention in a synoptic manner.

FIG. 2 is a schematic view of a painting apparatus with electrodeaccording to the invention and it is intended as a model for operationaccording to the invention.

FIG. 3 is a cross-section view of one embodiment of the electrodeaccording to the instant invention.

FIG. 4 is a front-view of the electrode according to FIG. 3.

FIG. 5 is a cross-section view of a second embodiment of the electrodeaccording to the instant invention.

FIG. 6 is a front-view according to FIG. 5.

FIG. 7 is a cross-section view of an electrical field generation by anelectrode according to the instant invention.

FIG. 8 is another embodiment of an electrode according to the instantinvention.

FIG. 9, shown from above and schematically, is a heating chamber of thepainting apparatus according to the instant invention.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, we apply the method the subject of this invention to aparticular example: furniture wood. This furniture wood can be of M.D.F.(medium density fiber); in other words, a wood made in part from citrusfruit trees compressed under high pressure. This wood can also be afiberboard and, more generally, any type of natural or recomposed woodused in furniture making. The part to be painted, as one can seeparticularly in FIG. 2, can be in the form of a polygon-shaped board,for example rectangular or square.

In FIG. 1 we have: the cut-out and formation (1), the drilling (2), thesanding and protection (3) of the edges, the sanding (4) of the entirepart, the attachment (5) of the electrode, the application (6) ofelectrical tension on the electrode, the application (7) of electricaltension on the paint, the spraying (8) of the paint, the heating at lowflow (9), the heating at increased flow (10), the cutting (11) of theedges and the application (12) of a glaze.

The cut-out and formation (1) exists in the prior art. It could involve,for example, cutting the part in a rectangular shape, rounding its edgesand finally shaping by means of cuts and grooves. This gives the partits definitive shape. The other operations address the surface of thepart to be painted. The wood to be used should preferably have anhygrometry of 8% to 12%.

The drilling (2) involves creating an initial hole in the part to bepainted (without splitting the wood) in order to insert the electrode.The drilling will create a recessed hole and, where the part to bepainted is a board, it will be drilled such that its median axis ofsymmetry runs perpendicular to the two large faces of the board.

The drilling (2) for the electrodes shall be done either in an area thatwill later be further manufactured or an area that will be eliminatedwhen the edges are cut. Preferably, the drilling for the electrode isthen used, for example, for the hanging of a door hinge or some otherhinge or mechanical element used in the assembly of the boards of apiece of furniture. Where the electrode is affixed directly to the partto be painted, no drilling is done. Drilling is likewise not done if theshape of the electrode allows for its insertion into the part to bepainted without risk of splitting the latter.

The protection of the edges (3) of the board is a characteristicoperation of the instant invention. The edges of the piece of wood aresanded, for example with a sand paper of 400 grain for the M.D.F. and of220 grain for the fiberboard, then they are covered with a sealant suchas a barium-based wood paste or a polyurethane-based varnish. Thisprocess involves, therefore, sealing the pores of the wood, or fillingin the uneven surfaces of the wood. This protection (3) of the edgesalso includes a drying period which may last several hours. Thisprotection allows the pieces of wood to stand up to heating, even athigh temperatures.

The sanding (4) is also one of the characteristic operations of theinstant invention. The sanding is an action of preparing the surfaceprior to applying a product The sanding eliminates fibers, impurities,grease and grooves from the surface. This sanding is done according tothe method of the instant invention with a sand paper of at least 300grain, and, preferably of 400 grain This grain corresponds to aparticular sanding operation called "egrenage" because of the finenessof the grain used. This sanding is done on all surfaces to be painted.The fineness of the grain allows for the fibers of the wood not to beopened to such an extent that, when heated in heating operations 9 and10, there is any bubbling or significant evaporation. Thus, the state ofthe surface of the paint is not altered. When using a board, all sidesare sanded.

The attachment of the electrode (5) involves mechanically fixing, andthus electrically fixing, the electrode to the part to be painted.According to the preferred embodiment, the electrode is inserted,preferably by force, into the hole created by drilling (2). Thisinsertion can be done, for example, by driving or screwing. Theelectrode contains rigid or curved protrusions or acute angles. Theelectrode, therefore, contains certain concave parts. This operation isthe principle characteristic of the invention because the shape of theelectrode favors the development of either a spherical or a flatelectrical field around the electrode once it is joined with a powersource.

The application (6) of electrical tension on the electrode involveselectrically joining the electrode with a source of electrical power.Generally, it is preferred that the tension be zero. Preferably, theelectrode is joined to said power source by an electrical cable ormetallic support

The application of electrical tension on the paint (7) is done by amethod known in the prior art. It involves electrically chargingpowdered paint, such as a polyester powder, with an opposite charge fromthat which charges the part to be painted, said electrical tension beingdelivered by the source of power to which the electrode is attached.

In this way, the equipotential lines are distributed throughout the partto be painted and one of them is practically identical to the volume ofthe part to be painted. It is notable that said effect applies to thepart to be painted and, thus, the corners are painted in the same way asthe rest of the part, if not better.

The spraying of the paint (8) is known in the prior art and is generallydone using an electrostatic paint gun. It is the force of the spray, thestatic electricity and the electrical field created between theelectrode and the gun that cause the movement of the powdered painttowards the part to be painted. Said electrostatic paint gun isconnected to the source of power and is configured such that itelectrically charges the paint whether the polarity is positive ornegative.

The spraying of the paint is caused by sweeping, but the sprayedpowdered paint coats with only one layer.

The heating at low flow (9) is done initially in a heating chamber intowhich the painted parts are introduced. The flow of hot air, which comesfrom the bottom of the chamber is checked by a mechanical protectionThus, the thermal shock is limited, as is the mixture of air which coulddisturb the uniformity of the distribution of the paint. This heating islimited to a very short time, approximately two to four minutes, duringwhich the paint begins to adhere to the support.

The process of heating at increased flow (10) exists in the prior art.It takes place in the rest of the chamber. The two types of heating aredone, for example, in a gas oven but it goes without saying that anytype of heating chamber adapted for this function could be used.Finally, in the case of parts sold in panels, the cutting (11) of theedges allows for the pieces to meet the required dimensions and for theelimination of the drilled hole (2) created for the electrode.

The application (12) of varnish exists in the prior art, and is done,for example, by blower, by roller, by automatic or manual spray gun.

It is obvious from the description of FIG. 1 that the characteristicstages of the method are in order of decreasing importance.

the use of an electrode which contains rigid or curved protrusions oracute angles and which, thus, favors the development of either aspherical or a flat electrical field around the electrode once it isjoined to a power source.

the sanding done with a sand paper of at least 300 grain, and,preferably of 400 grain, corresponding also to a method called"egrenage". This sanding lessens the roughness of the surface withoutmaking buckling possible at the time of heating.

the protection of the edges (3) which are covered with a wood pastewhich may be diluted or with a polyurethane varnish This process,therefore, involves sealing the pores of the wood, or filing in theuneven surfaces of the wood. This protection of the edges also includesa drying period which may last several hours.

In FIG. 1, the method the subject of this invention is applied to aparticular example, that of furniture wood. However, other examplescould be used such as plaster, compost, brick, polyvinyl chloride, tileand, more generally, any materially that is a poor conductor.

This method according to the instant invention could also be applied tocardboard products made from shredded materials mixed with a urea-basedglue and heat compressed. The shredded materials could be folded boxeslined with a sheet of aluminum.

It is important to note that the paint can be metallic and/or cause theplating of the part to be painted or some other effect such as agranular, a hammered, a shaped or a smooth appearance.

The products made according to the method described by FIG. 1 havesuccessfully withstood resistance tests with shocks of ball bearings ofup to 110 grams, tests for qualifications of lacquer paints andvarnishes, adhesion trials by section on varnish or lacquer, resistancetests using scratching, cigarette burns, stains with domestic productsand food products.

According to one variation, the method includes a varnish stage usingclear vanish which dries to display ultraviolet radiation with abrilliance of 25% to 100%, according to the selection of the user,without requiring additional sanding. The grams per meter squared reachbetween 90 and 160 ideally with a precision and homogeneity of 10 grams.

According to a second variation, the method includes a varnish stagewhere a polyurethane varnish of traditional drying or a diluted woodpaste of traditional drying is applied.

According to these two variations, the application could be done, forexample, by robot, by blower, by spray gun or manually.

FIG. 2 is a schematic representation of a painting apparatus accordingto the invention.

FIG. 2 represents a paint spraying unit (13), a part to be painted (16),an electrode (17), a support for the electrode (18) and a power source(19), the paint (20), a stream of paint (21), a compressor (45) and atank for powder (46) constituting a paint (20) supply.

The paint spraying unit (13) is configured so as to direct the stream ofelectrically-charged paint (21) towards the part (16) to be painted. Itis of a type known in the prior art. This paint spraying unit containsan internal chamber housed within a projection gun and connected both toa paint outlet at one end and to a paint supply (46) by way of aconduit. The paint, in powdered form, is fed, using compressed airthrough the chamber from the paint supply (46) to the outlet. Within thechamber in the paint spraying unit is an electrode, not shown, which iselectrically connected by the electric cascade of the paint sprayingunit to the positive pole of the electric power source (19). The otherpole of the power source (19) is electrically connected to the electrode(17) either directly or indirectly by way of the support (18). Betweenthe electrode (17) and the electrode of the paint spraying unit,therefore, an electrostatic field is created which can be negatively orpositively charged according to the selection of the electric cascade.The paint becomes electrically charged as it passes through the chamberand comes in proximity to or in contact with the electrode of the paintspraying unit. Preferably, the electric power source provides betweenits terminals a potential difference of several tens of kilovolts.

Step 8 of FIG. 1, involves the spraying of the paint onto the part to bepainted. The part has, therefore, already been sanded with a sand paperof at least 300 grain and the roughness of its edges has been plugged.

The compressor (45) injects the compressed air into the powder supply(46) according to techniques existent in the prior art in order toconvert the powder into aerosol The aerosol then passes into the paintspraying unit.

The support (18) for the electrode is configured so as to mechanicallysupport the electrode (17) and the part to be painted (16) and so as toelectrically connect one of the electrical terminals of the power source(19) to the electrode (17). The electrode (17) favors the development ofeither a spherical or a flat electrical field around itself once it isjoined to the power source. The electrode (17) is conductive andcontains jagged portions, such as for instance, rigid or curvedprotrusions or acute angles. Thus the electrode (17) contains certainconcave parts. It is connected electrically to an electrical mass and tothe part to be painted (16). The negative pole of the power source (19)will be connected to said electrical mass. It also serves as a supportfor the part to be painted (16).

Each protrusion which is a part of the electrode (on its surface,according to a normal plan) could have an acute triangular ortrapezoidal section or any such form presenting a region of strongcurvature at a distance from said surface.

Each protrusion could be in the form of a spike and project at a rightangle from the surface of the electrode or could be curved, for examplecircular, helix-shaped or curved in some other manner.

The electrode could contain a core with the protrusion(s) being locatedon the exterior surface of the core and being spread out radially aboutsaid surface. Such an electrode with core is intended to be insertedinto the hole previously made in the part to be painted.

Such an electrode, once it is connected mechanically and electrically toa part, i.e. a polygonal board, of which all of the exterior surfacesare to be painted, is inserted into the board preferably in thedirection of the width of the board. The longitudinal axis of the coreof the electrode is, therefore, perpendicular to the two large faces ofthe board.

The core could be in the shape of a long, rectangular figure, butpreferably the core would be cylindrical or conical The protrusions ofan electrode with cylindrical or conical core could each form, accordingto one of the generators of the exterior cylindrical or conical surfaceof the core, or also, they could form in a curved manner on saidexterior surface, for example, in helix-shape, in circle or otherwise.The protrusions of an electrode with cylindrical or conical core couldalso be composed of spikes forming radially with respect to the core.

FIG. 3 is a cross-section view of a preferred embodiment of theelectrode the subject of this invention. FIG. 4 is a front-view of thesame embodiment of the electrode. Said electrode, with cylindrical core,has external threading and at least one longitudinal groove extendingalong the generator of the core and through threading of the screw.

FIG. 3 and FIG. 4 show a part to be painted (16), an electrode (17) witha cylindrical core, external threading (22, 23, 24, 25), at least onegroove, an internal cavity (28), internal threading (29), a front end(30) and a rod (32). Preferably, the electrode will have two grooves(26, 27) which are diametrically opposed. The electrode could beequipped with a greater number of grooves which would be spacedequidistant from one another. Note: the length of the electrode dependsupon the width of the part to be painted.

The part to be painted (16) is pierced by a hole of a diameter roughlyequal to the diameter of the base of the electrode accounting for thestring of external threadings (22, 23, 24 and 25) and its depth isroughly equal to or superior to the length of the portion of theelectrode to be inserted into the board.

The external threadings (22, 23, 24 and 25) and the two grooves (26 and27) are formed according to a unique pattern whereby the distancebetween two consecutive points of intersection of the circular helix isapproximately 1 mm. Each piece of threading (22, 23, 24 and 25) is,therefore, roughly of the same length as the others, but shorter thanone half the distance between two consecutive points of intersection ofthe circular helix created by grooves 26 and 27. The electrode (17)contains, therefore, curved and helicoidal protrusions and acute angles.

The cylindrical internal cavity (28) crosses the electrode along thelongitudinal median axis of the core of the latter.

The electrode, as it is represented in FIG. 3, does not contain ashouldering, but it could be outfitted with one to limit the electrode'spenetration into the part to be painted (16).

The internal threading (29), or screw cutting, extends the entire lengthof the internal cavity (28).

The metallic rod (32) allows for the insertion of the electrode (17)into the part to be painted (16) due to its shape and the connection ofelectrical connectors to the electrode (17). Preferably, the rod (32) iscylindrical and has a jagged threading at one end for screwing thatextremity into the internal threading (29) of the electrode (17). Saidrod (32) ensures an electrical and mechanical connection between theelectrode and the support for the electrode (18). Said rod can alsoserve as a support for the electrode.

The electrode (17) according to FIGS. 3 and 4 is preferably inserted byscrewing. Due to the presence of the grooves, the electrode according tosuch an embodiment is self-screwing and its screwing into the holecauses the screwing of the latter. Thus, the thread-shaped protrusionsof this electrode penetrate completely the material of the board and arein direct contact with the part to be painted which improves both theelectrical and mechanical connections of the board.

Preferably, the depth of insertion of the electrode (17) into the holedrilled in the part to be painted (16) is roughly greater than one-halfthe width of the part to be painted and roughly less than said width.

FIG. 5 is a cross-section view of a second embodiment of the electrodethe subject of this invention.

FIG. 6 is a front-view of the electrode shown in FIG. 5.

FIGS. 5 and 6 show a part to be painted (16), an electrode (17) with acore having straight, longitudinal external protrusions along itssurface (33) separated by longitudinal crevices (34), an internal cavity(35), a shouldering (31) and a rod (32). This electrode contains acylindrical core.

The straight, longitudinal external protrusions (33) and the crevices(34) form a polygonal-based prism, for example in the shape of a star.The internal cavity (35) crosses the electrode and extends along thelongitudinal axis of the core of the latter. The shouldering (31) andthe rod (32) which is cut jaggedly along one extremity have the samecharacteristics and functions as in FIGS. 3 and 4.

Preferably, the electrode (17) shown in FIGS. 5 and 6 is forciblyinserted into a pre-made hole in the board. The electrode (17),therefore, contains straight protrusions and acute angles.

Other embodiments of the electrode could conform to the spirit of theinvention, such as wood screws, threaded rods, and the like.

As shown in FIG. 8, one could also envision an electrode in the form ofa thin, polygon-shaped plate with its external protrusions being locatedalong at least one of the faces of the plate. Such an electrode could beforcibly inserted into the wooden board without any drilling of thelatter, or could be inserted into an opening created by drilling orcould be attached to one of the faces of the board. The protrusions ofsaid thin, plate-like electrode could be spike-like studs or the like.The protrusions will always contain a straight triangular or trapezoidalsection or a section of some shape to serve as the location of peakelectrostatic effect.

The plate could contain a series of protrusions and crevices such thatit would be rippled. The ripples of the plate could be triangular. Thebroad faces of the ripples could be smooth or could have their ownprotrusions such as those already described.

FIG. 7 is a cross-section view of an electrical field generated by anapparatus according to the instant invention.

FIG. 7 shows the equipotential lines (36, 37 and 38) generated when theinserted portion of the electrode (17) is placed under tension.

These equipotential lines (36, 37 and 38) are elliptical and, in space,their surface is ellipsoidal.

It is apparent that once the electrode (17) is inserted into the part tobe painted (16), the lines of the field will take on a flattened form,and that one of them will be roughly identical in form to the part to bepainted (16). This is due to the dielectricity of the material of thepart to be painted (16) or to its poor conductivity.

FIG. 9 is a paint heating chamber according to the instant invention.

FIG. 9 shows a heating chamber (39), a zone of entry for the parts (40),an outlet zone for the parts (41), an area of heating at increased flow(42) and a path for the hot air (43) equipped with a protection (44).

The heating chamber (39) contains a zone of entry for the parts (40)which is, for example, at one end of the heating chamber while theoutlet zone for the parts (41) is at the other end. Between these twozones, an intermediate zone (42) extends. In this heating chamber (39),the first phase of heating or cooking involves lower speeds of air flowthan do the subsequent phases of heating or cooking in order that thepaint can gel before the part enters the zone of strong air flow. Thefirst phase of heating occurs in the zone where the air enters, whereasthe next phase occurs in the rest of the chamber, in zones 42 and 41. Itis important to note that the entire volume of the heating chamber is atthe same temperature.

The zone of heating at increased flow (42) includes both zones 42 and41. According to the preferred embodiment, the heating chamber isequipped all over with openings for air to enter; the entrance of theair taking place at the bottom and the openings being throughout zones40, 41 and 42. In order that the flow of air be slowed in the zone ofentry, said zone is equipped with a screen made up of an immobilepartition placed at the base of zone 40 to cover the openings for air toenter said zone. According to this method and apparatus for heating, theparts to be painted (16) are subjected first to heating without thermalshock or mixing of air as these two events could cause the deteriorationof the paint on the surface of the parts (16) given that the paint isstill in solid powder form on the surface of the parts (16).

It is important to note that the temperatures and heating times to beused are those that are recommended for the powdered paint to be usedbecause the wood, once its edges have been treated and its rigidplugged, can withstand quite high temperatures without thermaldilatation.

The method and apparatus described in the instant invention can be usedfor painting fiberboard, compressed wood, fiberboard coated with apolyvinyl film such as polished polyvinyl chloride or an imitation oil,wood of medium density fiber whether coarse or smooth or coated withpolyvinyl chloride or an imitation oil or a natural veneer.

It is important to note that the electrode can be a part of the finishedproduct and, therefore, would not have to be removed from the board.Said electrode in this case could eventually serve as a brace for theboard.

I claim:
 1. A method for painting a part of a dielectric material withpaint in powder form using a paint spraying unit, the paint sprayingunit having a chamber connected both to a paint outlet and to a paintsupply, an electrode is housed in the chamber and is electricallyconnected to a first pole of a power source, the methodcomprising:forming another electrode having a cylindrical or taperedcore, said another electrode having angular protrusions on an externalsurface of said core; inserting and connecting said angular protrusionsof said another electrode mechanically and electrically in a thicknessof the part; connecting said another electrode electrically to a secondpole of the power source; creating an electrostatic field between saidanother electrode and the paint spraying unit by applying a potentialdifference between said another electrode and the electrode housed inthe chamber of the paint spraying unit; feeding the paint in powder formfrom the paint supply towards the paint outlet by passage through thechamber of the paint-spraying unit; electrically charging the paint withsaid electrode during the passage through the chamber; and directing thepaint towards at least one surface of the part.
 2. The method of claim1, the step of connecting comprising the step of:placing said anotherelectrode on at least one external face of the part.
 3. The method ofclaim 2, further comprising the step of:sanding said surface of the partprior to the step of directing the paint.
 4. The method of claim 3, saidat least one surface of the part having grooves along edges thereof, themethod further comprising the step of:applying a sealant to the groovesprior to the step of directing the paint.
 5. A system forelectrostatically painting with paint in powder form, the systemcomprising:a part made of a dielectric material; an electric powersource having two poles; a paint spraying unit having a central chamberwith a first electrode therein, said first electrode being connected toa first pole of said two poles of said power source,; and a secondelectrode connected to a second pole of said two poles of said electricpower source, said second electrode having a cylindrical or taperedcore, said second electrode having angular protrusions formed on anexternal surface of said core, said angular protrusions engaged with thepart.
 6. The system of claim 5, each of said protrusions being longiformand projecting rectilinearly.
 7. The system of claim 5, said protrusionsforming a helix shape in said external surface of said core.
 8. Thesystem of claim 5, said core having external threading with alongitudinal groove extending along said core across said externalthreading.
 9. The system of claim 5, said second electrode having a formof a plate, said protrusions located on at least one face of said form.10. The system of claim 5, said second electrode being a rippled form.11. The system of claim 10, each ripple of said rippled form of saidsecond electrode being of a generally triangular configuration.